[mrtg] Re: SNMP and Cisco ... Oh the Fun a newbie can have.

Tue Aug 31 20:39:33 MEST 2004

This is (all to often) the normal case for a Cisco 6500 switch/router.
The issue is that, in the most common case, the 6500 is only routing the
first few packets of a given 'conversation'; after that they are switched.
So the traffic counters for the Virtual router Interface are pretty much
useless. 

The only ways I know around this are to either install some fancy hardware
(Multi-Flow Feature Card?) and matching software; or to disable that part of
the 'switching' function. I seem to recall having some luck with disabling
CEF on that router port---WARNING: this will have a severe negative impact
on router performance! Do not do this lightly.

-Benjamin

-----Original Message-----
From: Moses Hernandez [mailto:moses_hernandez at hotmail.com] 
Sent: Tuesday, August 31, 2004 9:00 AM
To: Eric_Mailing_List at rednarb.com; mrtg at list.ee.ethz.ch
Subject: [mrtg] Re: SNMP and Cisco ... Oh the Fun a newbie can have.

Hmm actually let me do that. Here is what i have right now on one of my 
interfaces:

### Interface 107 >> Descr: 'DataCenter 2MDF-SW1' | Name: '3/1' | Ip: '' | 
Eth: '00-0d-28-3f-8b-b8' ###
### The following interface is commented out because:
Target[10.4.0.4_107]: 107:c1sc0 at 10.4.0.4:161::::2
SetEnv[10.4.0.4_107]: MRTG_INT_IP="" MRTG_INT_DESCR="DataCenter 2MDF-SW1"
MaxBytes[10.4.0.4_107]: 1000000000
Title[10.4.0.4_107]:  DataCenter 2MDF-SW1  -- MIA_6K_MDF1
PageTop[10.4.0.4_107]: <H1> DataCenter 2MDF-SW1  -- MIA_6K_MDF1</H1>
Options[10.4.0.4_107]: bits, unknaszero
YLegend[10.4.0.4_107]: Port Utilization
LegendI[10.4.0.4_107]: In
LegendO[10.4.0.4_107]: Out
Legend1[10.4.0.4_107]: Inbound Bits
Legend2[10.4.0.4_107]: Outbound Bits
Legend3[10.4.0.4_107]: INBOUND Max value per interval on graph
Legend4[10.4.0.4_107]: OUTBOUND Max value per interval on graph
Colours[10.4.0.4_107]: GREEN#00eb0c,BLUE#0000ff,GRAY#AAAAAA,VIOLET#ff00ff
WithPeak[10.4.0.4_107]: ymw
<TABLE>
   <TR><TD>System:</TD>     <TD>MIA_6K_MDF1 in Mercy MDF</TD></TR>
   <TR><TD>Maintainer:</TD> <TD></TD></TR>
   <TR><TD>Description:</TD><TD>  </TD></TR>
   <TR><TD>ifType:</TD>     <TD>ethernetCsmacd (6)</TD></TR>
   <TR><TD>ifName:</TD>     <TD>3/1</TD></TR>
   <TR><TD>Port Name:</TD>  <TD>DataCenter 2MDF-SW1</TD></TR>
   <TR><TaD>Max Speed:</TD>  <TD>1000.0 MBytes/s</TD></TR> </TABLE>

Interestingly enough when i do a show port 3/1 (this is the CatIOS Side, 
Hybrid Mode) i do not see any counters that would reflect that. show 
spantree 3/1 shows forwarding in all of the vlans but the graph at the 
momment display about

Max In  8753.5 kb/s (0.1%)   Average In  3592.3 kb/s (0.0%)   Current In  
4237.3 kb/s (0.1%)
Max Out  1520.6 kb/s (0.0%)   Average Out  1205.6 kb/s (0.0%)   Current Out

1207.2 kb/s (0.0%)

is that correct? I mean seems awfully low so what i did was telneted to the 
other side and looked at the gigabit uplink. This is what i see for 5 
minutes

5 minute input rate 1238000 bits/sec, 933 packets/sec
  5 minute output rate 3966000 bits/sec, 978 packets/sec

Is there something i am missing maybe? or are these numbers accurate and 
that switch has little to no traffic maybe?

Mind you the biggest traffic generation is between the 2 cores and i've seen

the max 50MB/s with the links being Gigabit.

>From: Eric Brander <Eric_Mailing_List at rednarb.com>
>To: mrtg at list.ee.ethz.ch
>Subject: [mrtg] Re: SNMP and Cisco ... Oh the Fun a newbie can have.
>Date: Tue, 31 Aug 2004 10:06:06 -0500
>MIME-Version: 1.0
>Moses Hernandez wrote:
>
> > I have started using mrtg on a win32 test box. It has been running 
> > for 5 days on the core router 6500 router side, two remote connect 
> > routers and
>the
> > internet firewall. Today I configured the 6500 gigabit switchports 
> > to
>also
> > get snmp info. I have noticed not much traffic above the 640.0 K 
> > usage, maybe 1.2M. I am using mrtg 2.10.15 and I thought it was a 
> > versioning
>issue
> > but noticed some others in the archive had similar issues though no 
> > resolution. As an aside the low numbers are showing up on my nokia
>firewalls
> > and the numbers are kind of inconsistance with the bandwidth stats 
> > from
>my
> > isp.

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